docs: def _chown(self, path, uid, gid):
          """Change the *owner* of a resource.
          """
          if uid is None or gid is None:
              info = self.getinfo(path, namespaces=('access',))
              uid = uid or info.get('access', 'uid')
              gid = gid or info.get('access', 'gid')
          self._sftp.chown(path, uid, gid)